1. Field of the Invention
The present invention relates to an electro-photographic image forming apparatus such as a copying machine, a printer, a facsimile, or a multi-functional peripheral thereof, to a lubricant supplying device installed therein, and also to a process cartridge.
2. Description of the Related Art
Hitherto, in an image forming apparatus such as a copying machine or a printer, there is a known technique using a lubricant supplying device which supplies a lubricant to an image carrier such as a photosensitive drum or an intermediate transfer belt (for example, see Japanese Patent Application Laid-open No. 2006-201565 and Japanese Patent Application Laid-open No. 2001-305907).
Specifically, non-transferred toner which remains on a photosensitive drum after a transfer process needs to be completely removed by a cleaning blade (a cleaning device) which comes into contact with the photosensitive drum. However, in a case in which a contact portion of the cleaning blade is chipped (damaged) due to the friction against the photosensitive drum, the non-transferred toner goes through a gap between the damaged cleaning blade and the photosensitive drum, which results in a cleaning defect.
In order to solve this problem, a method may be considered in which a lubricant is coated onto the photosensitive drum so as to reduce a friction coefficient on the photosensitive drum. This method reduces the abrasion and the damage of the cleaning blade or the deterioration of the photosensitive drum, and as a result, the cleaning defect with an elapse of time may be suppressed.
Specifically, in Japanese Patent Application Laid-open No. 2006-201565 and Japanese Patent Application Laid-open No. 2001-305907, a lubricant coating device includes: a brush roller (a lubricant supplying roller) which slides on a photosensitive drum (an image carrier); a solid lubricant which comes into contact with the brush roller; a holding member which holds the solid lubricant; and a compressing spring which biases the solid lubricant and the holding member in the press-contact direction toward the brush roller. Then, the lubricant is gradually scraped off the solid lubricant by the brush roller which rotates in a predetermined direction, and the lubricant which is scraped off and conveyed by the brush roller is coated on (supplied to) the surface of the image carrier. Here, the compressing springs which bias the solid lubricant in the press-contact direction are provided at both end portions of a casing, respectively in the width direction between the casing (the exterior cover) and the holding member which holds the solid lubricant.
In the lubricant supplying device of the related arts, since the compressing springs which are used to bias the solid lubricant in the press-contact direction are attached to the casing in a manner that the compressing springs may not be seen between the holding member and the casing, the compressing springs are attached to the casing in a buckled state or the compressing springs slip off the casing, which easily results in the defective assembly of the compressing springs. Then, when such problems arise, the original function of the lubricant supplying device may not be exhibited.